Amazon redshift 红移。将逗号分隔的值转换为包含所有组合的行
我有: 我想看看:Amazon redshift 红移。将逗号分隔的值转换为包含所有组合的行,amazon-redshift,Amazon Redshift,我有: 我想看看: user_id|user_name|user_action ----------------------------- 1 | Shone | start,stop,cancell 您可以创建以下Python UDF: user_id|user_name|parsed_action ------------------------------- 1 | Shone | start 1 | Shone | start,stop
user_id|user_name|user_action
-----------------------------
1 | Shone | start,stop,cancell
您可以创建以下Python UDF:
user_id|user_name|parsed_action
-------------------------------
1 | Shone | start
1 | Shone | start,stop
1 | Shone | start,cancell
1 | Shone | start,stop,cancell
1 | Shone | stop
1 | Shone | stop,cancell
1 | Shone | cancell
....
它将接受您的操作列表并返回由分号分隔的唯一组合,而组合本身将由逗号分隔。然后使用UNION hack将值拆分为单独的行,如下所示:
create or replace function get_unique_combinations(list varchar(max))
returns varchar(max)
stable as $$
from itertools import combinations
arr = list.split(',')
response = []
for L in range(1, len(arr)+1):
for subset in combinations(arr, L):
response.append(','.join(subset))
return ';'.join(response)
$$ language plpythonu;
WITH unique_combinations as (
SELECT
user_id
,user_name
,get_unique_combinations(user_actions) as action_combinations
FROM your_table
)
,unwrap_lists as (
SELECT
user_id
,user_name
,split_part(action_combinations,';',1) as parsed_action
FROM unique_combinations
UNION ALL
SELECT
user_id
,user_name
,split_part(action_combinations,';',2) as parsed_action
FROM unique_combinations
-- as much UNIONS as possible combinations you have for a single element, with the 3rd parameter (1-based array index) increasing by 1
)
SELECT *
FROM unwrap_lists
WHERE parsed_action is not null